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dd82109 @gregkh added md5.c and md5.h from coreutils 6.9 release.
authored
1 /* Functions to compute MD5 message digest of files or memory blocks.
2 according to the definition of MD5 in RFC 1321 from April 1992.
3 Copyright (C) 1995,1996,1997,1999,2000,2001,2005,2006
4 Free Software Foundation, Inc.
5 This file is part of the GNU C Library.
6
7 This program is free software; you can redistribute it and/or modify it
8 under the terms of the GNU General Public License as published by the
9 Free Software Foundation; either version 2, or (at your option) any
10 later version.
11
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
16
17 You should have received a copy of the GNU General Public License
18 along with this program; if not, write to the Free Software Foundation,
19 Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
20
21 /* Written by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1995. */
22
f3f956d @gregkh add md5 to build
authored
23 //#include <config.h>
dd82109 @gregkh added md5.c and md5.h from coreutils 6.9 release.
authored
24
25 #include "md5.h"
26
27 #include <stddef.h>
28 #include <stdlib.h>
29 #include <string.h>
30 #include <sys/types.h>
31
32 #if USE_UNLOCKED_IO
33 # include "unlocked-io.h"
34 #endif
35
36 #ifdef _LIBC
37 # include <endian.h>
38 # if __BYTE_ORDER == __BIG_ENDIAN
39 # define WORDS_BIGENDIAN 1
40 # endif
41 /* We need to keep the namespace clean so define the MD5 function
42 protected using leading __ . */
43 # define md5_init_ctx __md5_init_ctx
44 # define md5_process_block __md5_process_block
45 # define md5_process_bytes __md5_process_bytes
46 # define md5_finish_ctx __md5_finish_ctx
47 # define md5_read_ctx __md5_read_ctx
48 # define md5_stream __md5_stream
49 # define md5_buffer __md5_buffer
50 #endif
51
52 #ifdef WORDS_BIGENDIAN
53 # define SWAP(n) \
54 (((n) << 24) | (((n) & 0xff00) << 8) | (((n) >> 8) & 0xff00) | ((n) >> 24))
55 #else
56 # define SWAP(n) (n)
57 #endif
58
59 #define BLOCKSIZE 4096
60 #if BLOCKSIZE % 64 != 0
61 # error "invalid BLOCKSIZE"
62 #endif
63
64 /* This array contains the bytes used to pad the buffer to the next
65 64-byte boundary. (RFC 1321, 3.1: Step 1) */
66 static const unsigned char fillbuf[64] = { 0x80, 0 /* , 0, 0, ... */ };
67
68
69 /* Initialize structure containing state of computation.
70 (RFC 1321, 3.3: Step 3) */
71 void
72 md5_init_ctx (struct md5_ctx *ctx)
73 {
74 ctx->A = 0x67452301;
75 ctx->B = 0xefcdab89;
76 ctx->C = 0x98badcfe;
77 ctx->D = 0x10325476;
78
79 ctx->total[0] = ctx->total[1] = 0;
80 ctx->buflen = 0;
81 }
82
83 /* Put result from CTX in first 16 bytes following RESBUF. The result
84 must be in little endian byte order.
85
86 IMPORTANT: On some systems it is required that RESBUF is correctly
87 aligned for a 32-bit value. */
88 void *
89 md5_read_ctx (const struct md5_ctx *ctx, void *resbuf)
90 {
91 ((uint32_t *) resbuf)[0] = SWAP (ctx->A);
92 ((uint32_t *) resbuf)[1] = SWAP (ctx->B);
93 ((uint32_t *) resbuf)[2] = SWAP (ctx->C);
94 ((uint32_t *) resbuf)[3] = SWAP (ctx->D);
95
96 return resbuf;
97 }
98
99 /* Process the remaining bytes in the internal buffer and the usual
100 prolog according to the standard and write the result to RESBUF.
101
102 IMPORTANT: On some systems it is required that RESBUF is correctly
103 aligned for a 32-bit value. */
104 void *
105 md5_finish_ctx (struct md5_ctx *ctx, void *resbuf)
106 {
107 /* Take yet unprocessed bytes into account. */
108 uint32_t bytes = ctx->buflen;
109 size_t size = (bytes < 56) ? 64 / 4 : 64 * 2 / 4;
110
111 /* Now count remaining bytes. */
112 ctx->total[0] += bytes;
113 if (ctx->total[0] < bytes)
114 ++ctx->total[1];
115
116 /* Put the 64-bit file length in *bits* at the end of the buffer. */
117 ctx->buffer[size - 2] = SWAP (ctx->total[0] << 3);
118 ctx->buffer[size - 1] = SWAP ((ctx->total[1] << 3) | (ctx->total[0] >> 29));
119
120 memcpy (&((char *) ctx->buffer)[bytes], fillbuf, (size - 2) * 4 - bytes);
121
122 /* Process last bytes. */
123 md5_process_block (ctx->buffer, size * 4, ctx);
124
125 return md5_read_ctx (ctx, resbuf);
126 }
127
128 /* Compute MD5 message digest for bytes read from STREAM. The
129 resulting message digest number will be written into the 16 bytes
130 beginning at RESBLOCK. */
131 int
132 md5_stream (FILE *stream, void *resblock)
133 {
134 struct md5_ctx ctx;
135 char buffer[BLOCKSIZE + 72];
136 size_t sum;
137
138 /* Initialize the computation context. */
139 md5_init_ctx (&ctx);
140
141 /* Iterate over full file contents. */
142 while (1)
143 {
144 /* We read the file in blocks of BLOCKSIZE bytes. One call of the
145 computation function processes the whole buffer so that with the
146 next round of the loop another block can be read. */
147 size_t n;
148 sum = 0;
149
150 /* Read block. Take care for partial reads. */
151 while (1)
152 {
153 n = fread (buffer + sum, 1, BLOCKSIZE - sum, stream);
154
155 sum += n;
156
157 if (sum == BLOCKSIZE)
158 break;
159
160 if (n == 0)
161 {
162 /* Check for the error flag IFF N == 0, so that we don't
163 exit the loop after a partial read due to e.g., EAGAIN
164 or EWOULDBLOCK. */
165 if (ferror (stream))
166 return 1;
167 goto process_partial_block;
168 }
169
170 /* We've read at least one byte, so ignore errors. But always
171 check for EOF, since feof may be true even though N > 0.
172 Otherwise, we could end up calling fread after EOF. */
173 if (feof (stream))
174 goto process_partial_block;
175 }
176
177 /* Process buffer with BLOCKSIZE bytes. Note that
178 BLOCKSIZE % 64 == 0
179 */
180 md5_process_block (buffer, BLOCKSIZE, &ctx);
181 }
182
183 process_partial_block:
184
185 /* Process any remaining bytes. */
186 if (sum > 0)
187 md5_process_bytes (buffer, sum, &ctx);
188
189 /* Construct result in desired memory. */
190 md5_finish_ctx (&ctx, resblock);
191 return 0;
192 }
193
194 /* Compute MD5 message digest for LEN bytes beginning at BUFFER. The
195 result is always in little endian byte order, so that a byte-wise
196 output yields to the wanted ASCII representation of the message
197 digest. */
198 void *
199 md5_buffer (const char *buffer, size_t len, void *resblock)
200 {
201 struct md5_ctx ctx;
202
203 /* Initialize the computation context. */
204 md5_init_ctx (&ctx);
205
206 /* Process whole buffer but last len % 64 bytes. */
207 md5_process_bytes (buffer, len, &ctx);
208
209 /* Put result in desired memory area. */
210 return md5_finish_ctx (&ctx, resblock);
211 }
212
213
214 void
215 md5_process_bytes (const void *buffer, size_t len, struct md5_ctx *ctx)
216 {
217 /* When we already have some bits in our internal buffer concatenate
218 both inputs first. */
219 if (ctx->buflen != 0)
220 {
221 size_t left_over = ctx->buflen;
222 size_t add = 128 - left_over > len ? len : 128 - left_over;
223
224 memcpy (&((char *) ctx->buffer)[left_over], buffer, add);
225 ctx->buflen += add;
226
227 if (ctx->buflen > 64)
228 {
229 md5_process_block (ctx->buffer, ctx->buflen & ~63, ctx);
230
231 ctx->buflen &= 63;
232 /* The regions in the following copy operation cannot overlap. */
233 memcpy (ctx->buffer,
234 &((char *) ctx->buffer)[(left_over + add) & ~63],
235 ctx->buflen);
236 }
237
238 buffer = (const char *) buffer + add;
239 len -= add;
240 }
241
242 /* Process available complete blocks. */
243 if (len >= 64)
244 {
245 #if !_STRING_ARCH_unaligned
246 # define alignof(type) offsetof (struct { char c; type x; }, x)
247 # define UNALIGNED_P(p) (((size_t) p) % alignof (uint32_t) != 0)
248 if (UNALIGNED_P (buffer))
249 while (len > 64)
250 {
251 md5_process_block (memcpy (ctx->buffer, buffer, 64), 64, ctx);
252 buffer = (const char *) buffer + 64;
253 len -= 64;
254 }
255 else
256 #endif
257 {
258 md5_process_block (buffer, len & ~63, ctx);
259 buffer = (const char *) buffer + (len & ~63);
260 len &= 63;
261 }
262 }
263
264 /* Move remaining bytes in internal buffer. */
265 if (len > 0)
266 {
267 size_t left_over = ctx->buflen;
268
269 memcpy (&((char *) ctx->buffer)[left_over], buffer, len);
270 left_over += len;
271 if (left_over >= 64)
272 {
273 md5_process_block (ctx->buffer, 64, ctx);
274 left_over -= 64;
275 memcpy (ctx->buffer, &ctx->buffer[16], left_over);
276 }
277 ctx->buflen = left_over;
278 }
279 }
280
281
282 /* These are the four functions used in the four steps of the MD5 algorithm
283 and defined in the RFC 1321. The first function is a little bit optimized
284 (as found in Colin Plumbs public domain implementation). */
285 /* #define FF(b, c, d) ((b & c) | (~b & d)) */
286 #define FF(b, c, d) (d ^ (b & (c ^ d)))
287 #define FG(b, c, d) FF (d, b, c)
288 #define FH(b, c, d) (b ^ c ^ d)
289 #define FI(b, c, d) (c ^ (b | ~d))
290
291 /* Process LEN bytes of BUFFER, accumulating context into CTX.
292 It is assumed that LEN % 64 == 0. */
293
294 void
295 md5_process_block (const void *buffer, size_t len, struct md5_ctx *ctx)
296 {
297 uint32_t correct_words[16];
298 const uint32_t *words = buffer;
299 size_t nwords = len / sizeof (uint32_t);
300 const uint32_t *endp = words + nwords;
301 uint32_t A = ctx->A;
302 uint32_t B = ctx->B;
303 uint32_t C = ctx->C;
304 uint32_t D = ctx->D;
305
306 /* First increment the byte count. RFC 1321 specifies the possible
307 length of the file up to 2^64 bits. Here we only compute the
308 number of bytes. Do a double word increment. */
309 ctx->total[0] += len;
310 if (ctx->total[0] < len)
311 ++ctx->total[1];
312
313 /* Process all bytes in the buffer with 64 bytes in each round of
314 the loop. */
315 while (words < endp)
316 {
317 uint32_t *cwp = correct_words;
318 uint32_t A_save = A;
319 uint32_t B_save = B;
320 uint32_t C_save = C;
321 uint32_t D_save = D;
322
323 /* First round: using the given function, the context and a constant
324 the next context is computed. Because the algorithms processing
325 unit is a 32-bit word and it is determined to work on words in
326 little endian byte order we perhaps have to change the byte order
327 before the computation. To reduce the work for the next steps
328 we store the swapped words in the array CORRECT_WORDS. */
329
330 #define OP(a, b, c, d, s, T) \
331 do \
332 { \
333 a += FF (b, c, d) + (*cwp++ = SWAP (*words)) + T; \
334 ++words; \
335 CYCLIC (a, s); \
336 a += b; \
337 } \
338 while (0)
339
340 /* It is unfortunate that C does not provide an operator for
341 cyclic rotation. Hope the C compiler is smart enough. */
342 #define CYCLIC(w, s) (w = (w << s) | (w >> (32 - s)))
343
344 /* Before we start, one word to the strange constants.
345 They are defined in RFC 1321 as
346
347 T[i] = (int) (4294967296.0 * fabs (sin (i))), i=1..64
348
349 Here is an equivalent invocation using Perl:
350
351 perl -e 'foreach(1..64){printf "0x%08x\n", int (4294967296 * abs (sin $_))}'
352 */
353
354 /* Round 1. */
355 OP (A, B, C, D, 7, 0xd76aa478);
356 OP (D, A, B, C, 12, 0xe8c7b756);
357 OP (C, D, A, B, 17, 0x242070db);
358 OP (B, C, D, A, 22, 0xc1bdceee);
359 OP (A, B, C, D, 7, 0xf57c0faf);
360 OP (D, A, B, C, 12, 0x4787c62a);
361 OP (C, D, A, B, 17, 0xa8304613);
362 OP (B, C, D, A, 22, 0xfd469501);
363 OP (A, B, C, D, 7, 0x698098d8);
364 OP (D, A, B, C, 12, 0x8b44f7af);
365 OP (C, D, A, B, 17, 0xffff5bb1);
366 OP (B, C, D, A, 22, 0x895cd7be);
367 OP (A, B, C, D, 7, 0x6b901122);
368 OP (D, A, B, C, 12, 0xfd987193);
369 OP (C, D, A, B, 17, 0xa679438e);
370 OP (B, C, D, A, 22, 0x49b40821);
371
372 /* For the second to fourth round we have the possibly swapped words
373 in CORRECT_WORDS. Redefine the macro to take an additional first
374 argument specifying the function to use. */
375 #undef OP
376 #define OP(f, a, b, c, d, k, s, T) \
377 do \
378 { \
379 a += f (b, c, d) + correct_words[k] + T; \
380 CYCLIC (a, s); \
381 a += b; \
382 } \
383 while (0)
384
385 /* Round 2. */
386 OP (FG, A, B, C, D, 1, 5, 0xf61e2562);
387 OP (FG, D, A, B, C, 6, 9, 0xc040b340);
388 OP (FG, C, D, A, B, 11, 14, 0x265e5a51);
389 OP (FG, B, C, D, A, 0, 20, 0xe9b6c7aa);
390 OP (FG, A, B, C, D, 5, 5, 0xd62f105d);
391 OP (FG, D, A, B, C, 10, 9, 0x02441453);
392 OP (FG, C, D, A, B, 15, 14, 0xd8a1e681);
393 OP (FG, B, C, D, A, 4, 20, 0xe7d3fbc8);
394 OP (FG, A, B, C, D, 9, 5, 0x21e1cde6);
395 OP (FG, D, A, B, C, 14, 9, 0xc33707d6);
396 OP (FG, C, D, A, B, 3, 14, 0xf4d50d87);
397 OP (FG, B, C, D, A, 8, 20, 0x455a14ed);
398 OP (FG, A, B, C, D, 13, 5, 0xa9e3e905);
399 OP (FG, D, A, B, C, 2, 9, 0xfcefa3f8);
400 OP (FG, C, D, A, B, 7, 14, 0x676f02d9);
401 OP (FG, B, C, D, A, 12, 20, 0x8d2a4c8a);
402
403 /* Round 3. */
404 OP (FH, A, B, C, D, 5, 4, 0xfffa3942);
405 OP (FH, D, A, B, C, 8, 11, 0x8771f681);
406 OP (FH, C, D, A, B, 11, 16, 0x6d9d6122);
407 OP (FH, B, C, D, A, 14, 23, 0xfde5380c);
408 OP (FH, A, B, C, D, 1, 4, 0xa4beea44);
409 OP (FH, D, A, B, C, 4, 11, 0x4bdecfa9);
410 OP (FH, C, D, A, B, 7, 16, 0xf6bb4b60);
411 OP (FH, B, C, D, A, 10, 23, 0xbebfbc70);
412 OP (FH, A, B, C, D, 13, 4, 0x289b7ec6);
413 OP (FH, D, A, B, C, 0, 11, 0xeaa127fa);
414 OP (FH, C, D, A, B, 3, 16, 0xd4ef3085);
415 OP (FH, B, C, D, A, 6, 23, 0x04881d05);
416 OP (FH, A, B, C, D, 9, 4, 0xd9d4d039);
417 OP (FH, D, A, B, C, 12, 11, 0xe6db99e5);
418 OP (FH, C, D, A, B, 15, 16, 0x1fa27cf8);
419 OP (FH, B, C, D, A, 2, 23, 0xc4ac5665);
420
421 /* Round 4. */
422 OP (FI, A, B, C, D, 0, 6, 0xf4292244);
423 OP (FI, D, A, B, C, 7, 10, 0x432aff97);
424 OP (FI, C, D, A, B, 14, 15, 0xab9423a7);
425 OP (FI, B, C, D, A, 5, 21, 0xfc93a039);
426 OP (FI, A, B, C, D, 12, 6, 0x655b59c3);
427 OP (FI, D, A, B, C, 3, 10, 0x8f0ccc92);
428 OP (FI, C, D, A, B, 10, 15, 0xffeff47d);
429 OP (FI, B, C, D, A, 1, 21, 0x85845dd1);
430 OP (FI, A, B, C, D, 8, 6, 0x6fa87e4f);
431 OP (FI, D, A, B, C, 15, 10, 0xfe2ce6e0);
432 OP (FI, C, D, A, B, 6, 15, 0xa3014314);
433 OP (FI, B, C, D, A, 13, 21, 0x4e0811a1);
434 OP (FI, A, B, C, D, 4, 6, 0xf7537e82);
435 OP (FI, D, A, B, C, 11, 10, 0xbd3af235);
436 OP (FI, C, D, A, B, 2, 15, 0x2ad7d2bb);
437 OP (FI, B, C, D, A, 9, 21, 0xeb86d391);
438
439 /* Add the starting values of the context. */
440 A += A_save;
441 B += B_save;
442 C += C_save;
443 D += D_save;
444 }
445
446 /* Put checksum in context given as argument. */
447 ctx->A = A;
448 ctx->B = B;
449 ctx->C = C;
450 ctx->D = D;
451 }
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